package com.soundai.skill.helloworld.helper;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

public class Base64Util {
	private static final char[] base64EncodeChars = new char[] { 'A', 'B', 'C',
			'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
			'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c',
			'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
			'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2',
			'3', '4', '5', '6', '7', '8', '9', '+', '/' };

	private static byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1,
			-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
			-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
			-1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59,
			60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
			10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1,
			-1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
			38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1,
			-1, -1 };

	private Base64Util() {
	}

	/**
	 * 将字节数组编码为字符串
	 * 
	 * @param data
	 */
	public static String encode(byte[] data) {
		StringBuffer sb = new StringBuffer();
		int len = data.length;
		int i = 0;
		int b1, b2, b3;

		while (i < len) {
			b1 = data[i++] & 0xff;
			if (i == len) {
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
				sb.append("==");
				break;
			}
			b2 = data[i++] & 0xff;
			if (i == len) {
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[((b1 & 0x03) << 4)
						| ((b2 & 0xf0) >>> 4)]);
				sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
				sb.append("=");
				break;
			}
			b3 = data[i++] & 0xff;
			sb.append(base64EncodeChars[b1 >>> 2]);
			sb.append(base64EncodeChars[((b1 & 0x03) << 4)
					| ((b2 & 0xf0) >>> 4)]);
			sb.append(base64EncodeChars[((b2 & 0x0f) << 2)
					| ((b3 & 0xc0) >>> 6)]);
			sb.append(base64EncodeChars[b3 & 0x3f]);
		}
		return sb.toString();
	}

	/**
	 * 将base64字符串解码为字节数组
	 * 
	 * @param str
	 */
	public static byte[] decode(String str) {
		byte[] data = str.getBytes();
		int len = data.length;
		ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
		int i = 0;
		int b1, b2, b3, b4;

		while (i < len) {

			/* b1 */
			do {
				b1 = base64DecodeChars[data[i++]];
			} while (i < len && b1 == -1);
			if (b1 == -1) {
				break;
			}

			/* b2 */
			do {
				b2 = base64DecodeChars[data[i++]];
			} while (i < len && b2 == -1);
			if (b2 == -1) {
				break;
			}
			buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));

			/* b3 */
			do {
				b3 = data[i++];
				if (b3 == 61) {
					return buf.toByteArray();
				}
				b3 = base64DecodeChars[b3];
			} while (i < len && b3 == -1);
			if (b3 == -1) {
				break;
			}
			buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));

			/* b4 */
			do {
				b4 = data[i++];
				if (b4 == 61) {
					return buf.toByteArray();
				}
				b4 = base64DecodeChars[b4];
			} while (i < len && b4 == -1);
			if (b4 == -1) {
				break;
			}
			buf.write((int) (((b3 & 0x03) << 6) | b4));
		}
		return buf.toByteArray();
	}
	
	public static byte[] compress(String str)  {
  		if (str == null)
  			return null;

		ByteArrayOutputStream out = new ByteArrayOutputStream();
		GZIPOutputStream gzip;
		try {
			gzip = new GZIPOutputStream(out);
			gzip.write(str.getBytes());
			gzip.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
                    
          return out.toByteArray(); 
        /*
  		byte[] compressed;
  		ByteArrayOutputStream out = null;
  		ZipOutputStream zout = null;

  		try {
  			out = new ByteArrayOutputStream();
  			zout = new ZipOutputStream(out);
  			zout.putNextEntry(new ZipEntry("0"));
  			zout.write(str.getBytes());
  			zout.closeEntry();
  			compressed = out.toByteArray();
  		} catch (IOException e) {
  			compressed = null;
  		} finally {
  			if (zout != null) {
  				try {
  					zout.close();
  				} catch (IOException e) {
  				}
  			}
  		}
  		if (out != null) {
  			try {
  				out.close();
  			} catch (IOException e) {
  			}
  		}*/
  		//return compressed;
  	}
	
	 public static final String decompress(byte[] compressed) {
	  		if (compressed == null)
	  			return null;
	  		ByteArrayOutputStream out = new ByteArrayOutputStream();    
	        ByteArrayInputStream in = new ByteArrayInputStream(compressed);    
	        GZIPInputStream gunzip;
			try {
				gunzip = new GZIPInputStream(in);
				byte[] buffer = new byte[256];    
		        int n;    
		        while ((n = gunzip.read(buffer)) >= 0) {    
		          out.write(buffer, 0, n);    
		        }    				
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}    
	        // toString()使用平台默认编码，也可以显式的指定如toString("GBK")    
	        return out.toString(); 
	  		/*ByteArrayOutputStream out = null;
	  		ByteArrayInputStream in = null;
	  		ZipInputStream zin = null;
	  		String decompressed;
	  		try {
	  			out = new ByteArrayOutputStream();
	  			in = new ByteArrayInputStream(compressed);
	  			zin = new ZipInputStream(in);
	  			ZipEntry entry = zin.getNextEntry();
	  			byte[] buffer = new byte[1024];
	  			int offset = -1;
	  			while ((offset = zin.read(buffer)) != -1) {
	  				out.write(buffer, 0, offset);
	  			}
	  			decompressed = out.toString();
	  		} catch (IOException e) {
	  			decompressed = null;
	  		} finally {
	  			if (zin != null) {
	  				try {
	  					zin.close();
	  				} catch (IOException e) {
	  				}
	  			}
	  			if (in != null) {
	  				try {
	  					in.close();
	  				} catch (IOException e) {
	  				}
	  			}
	  			if (out != null) {
	  				try {
	  					out.close();
	  				} catch (IOException e) {
	  				}
	  			}
	  		}
	  		return decompressed;*/
	  	}	
	 
	 
}


